Decentralized Instant Messaging (Objective-C SDK)

Dependencies

• Latest Versions

Name	Version	Description
Ming Ke Ming (名可名)		Decentralized User Identity Authentication
Dao Ke Dao (道可道)		Universal Message Module
DIMP (去中心化通讯协议)		Decentralized Instant Messaging Protocol

Extensions

Content

extends CustomizedContent

ContentProcessor

#import <DIMSDK/DIMSDK.h>

NS_ASSUME_NONNULL_BEGIN

/*
 *  Customized Content Processing Unit
 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *  Handle content for application customized
 */
@interface DIMAppCustomizedProcessor : DIMCustomizedContentProcessor

- (void)setContentHandler:(id<DIMCustomizedContentHandler>)handler
                forModule:(NSString *)mod
            inApplication:(NSString *)app;

// protected
- (nullable id<DIMCustomizedContentHandler>)contentHandlerForModule:(NSString *)mod
                                                      inApplication:(NSString *)app;

@end

/*  Command Transform:

    +===============================+===============================+
    |      Customized Content       |      Group Query Command      |
    +-------------------------------+-------------------------------+
    |   "type" : i2s(0xCC)          |   "type" : i2s(0x88)          |
    |   "sn"   : 123                |   "sn"   : 123                |
    |   "time" : 123.456            |   "time" : 123.456            |
    |   "app"  : "chat.dim.group"   |                               |
    |   "mod"  : "history"          |                               |
    |   "act"  : "query"            |                               |
    |                               |   "command"   : "query"       |
    |   "group"     : "{GROUP_ID}"  |   "group"     : "{GROUP_ID}"  |
    |   "last_time" : 0             |   "last_time" : 0             |
    +===============================+===============================+
 */
@interface DIMGroupHistoryHandler : DIMCustomizedContentHandler

@end

NS_ASSUME_NONNULL_END

#import "DIMGroupCommand.h"

#import "DIMAppCustomizedProcessor.h"

static inline NSString *build_key(NSString *app, NSString *mod) {
    return [[NSString alloc] initWithFormat:@"%@:%@", app, mod];;
}

@interface DIMAppCustomizedProcessor () {
    
    NSMutableDictionary<NSString *, id<DIMCustomizedContentHandler>> *_handlers;
}

@end

@implementation DIMAppCustomizedProcessor

- (instancetype)initWithFacebook:(DIMFacebook *)facebook
                       messenger:(DIMMessenger *)transceiver {
    if (self = [super initWithFacebook:facebook messenger:transceiver]) {
        _handlers = [[NSMutableDictionary alloc] init];
    }
    return self;
}

- (void)setContentHandler:(id<DIMCustomizedContentHandler>)handler
                forModule:(NSString *)mod
            inApplication:(NSString *)app {
    [_handlers setObject:handler forKey:build_key(app, mod)];
}

- (nullable id<DIMCustomizedContentHandler>)contentHandlerForModule:(NSString *)mod
                                                      inApplication:(NSString *)app {
    return [_handlers objectForKey:build_key(app, mod)];
}

// Override
- (id<DIMCustomizedContentHandler>)filterApplication:(NSString *)app
                                          withModule:(NSString *)mod
                                             content:(id<DKDCustomizedContent>)body
                                            messasge:(id<DKDReliableMessage>)rMsg {
    id<DIMCustomizedContentHandler> handler;
    handler = [self contentHandlerForModule:mod inApplication:app];
    if (!handler) {
        // default handler
        handler = [super filterForModule:mod inApplication:app content:body messasge:rMsg];
    }
    return handler;
}

@end

@implementation DIMGroupHistoryHandler

// Override
- (NSArray<id<DKDContent>> *)handleAction:(NSString *)act
                                   sender:(id<MKMID>)uid
                                  content:(id<DKDCustomizedContent>)body
                                  message:(id<DKDReliableMessage>)rMsg {
    if ([body group] == nil) {
        NSAssert(false, @"group command error: %@, sender: %@", body, uid);
        NSString *text = @"Group command error.";
        return [self respondReceipt:text envelope:rMsg.envelope content:body extra:nil];
    } else if ([act isEqualToString:DIMGroupHistory_ActQuery]) {
        return [self transformQueryCommand:body message:rMsg];
    }
    NSAssert(false, @"unknown action: %@, %@, sender: %@", act, body, uid);
    return [super handleAction:act sender:uid content:body message:rMsg];
}

// private
- (NSArray<id<DKDContent>> *)transformQueryCommand:(id<DKDCustomizedContent>)body
                                           message:(id<DKDReliableMessage>)rMsg {
    DIMMessenger *transceiver = [self messenger];
    if (!transceiver) {
        NSAssert(false, @"messenger lost");
        return nil;
    }
    NSMutableDictionary *info = [body copyDictionary:NO];
    [info setObject:DKDContentType_Command forKey:@"type"];
    [info setObject:DKDGroupCommand_Query forKey:@"command"];
    id<DKDContent> query = DKDContentParse(info);
    if ([query conformsToProtocol:@protocol(DKDQueryGroupCommand)]) {
        return [transceiver processContent:query
                withReliableMessageMessage:rMsg];
    }
    NSAssert(false, @"query command error: %@, %@, sender: %@", query, body, rMsg.sender);
    NSString *text = @"Query command error.";
    return [self respondReceipt:text envelope:rMsg.envelope content:body extra:nil];
}

@end

ContentProcessorCreator

#import <DIMSDK/DIMSDK.h>

#import "DIMAppCustomizedProcessor.h"

NS_ASSUME_NONNULL_BEGIN

@interface DIMClientContentProcessorCreator : DIMContentProcessorCreator

@end

@interface DIMClientContentProcessorCreator (Customized)

// protected
- (DIMAppCustomizedProcessor *)createCustomizedProcessor:(DIMFacebook *)facebook
                                               messenger:(DIMMessenger *)transceiver;

@end

#import "DIMHandshakeCommandProcessor.h"

#import "DIMCreator.h"

#define CREATE_CPU(clazz)                                                      \
            [[clazz alloc] initWithFacebook:self.facebook                      \
                                  messenger:self.messenger]                    \
                                                   /* EOF 'CREATE_CPU(clazz)' */

@implementation DIMClientContentProcessorCreator

- (DIMAppCustomizedProcessor *)createCustomizedProcessor:(DIMFacebook *)facebook
                                               messenger:(DIMMessenger *)transceiver {

    DIMAppCustomizedProcessor *cpu = CREATE_CPU(DIMAppCustomizedProcessor);
    // 'chat.dim.group:history'
    [cpu setContentHandler:CREATE_CPU(DIMGroupHistoryHandler)
                 forModule:DIMGroupHistory_Mod
             inApplication:DIMGroupHistory_App];
    
    return cpu;
}

// Override
- (id<DIMContentProcessor>)createContentProcessor:(NSString *)type {
    // application customized
    if ([type isEqualToString:DKDContentType_Application] ||
        [type isEqualToString:DKDContentType_Customized]) {
        return [self createCustomizedProcessor:self.facebook messenger:self.messenger];
    }
    
    // ...
    
    // others
    return [super createContentProcessor:type];
}

// Override
- (id<DIMContentProcessor>)createCommandProcessor:(NSString *)name withType:(NSString *)msgType {
    // handshake
    if ([name isEqualToString:DKDCommand_Handshake]) {
        return CREATE_CPU(DIMHandshakeCommandProcessor);
    }
    
    // ...

    // others
    return [super createCommandProcessor:name withType:msgType];
}

@end

Usage

To let your DIMAppCustomizedProcessor start to work, you must override DIMContentProcessorCreator for message types:

1. DKDContentType_Application
2. DKDContentType_Customized

and then set your creator for DIMContentProcessorFactory in the DIMMessageProcessor.

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